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Image sensor
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<p>An image sensor or imager is a device that detects and conveys information used to form an image. It does so by converting the variable <a href="/facts/Attenuation/XP4vX360">attenuation</a> of light <a href="/facts/Wave/3ANn7WXS">waves</a> (as they <a href="/facts/Refraction/S8kvSKzM">pass through</a> or <a href="/facts/Reflection_(physics)/BhcjDs79">reflect off</a> objects) into <a href="/facts/Signal_(electrical_engineering)/41YqUJ8c">signals</a>, small bursts of <a href="/facts/Electric_current/Dc1xdnUX">current</a> that convey the information. The waves can be light or other <a href="/facts/Electromagnetic_radiation/Ynx7ujCW">electromagnetic radiation</a>. Image sensors are used in <a href="/facts/Electronics/E4JhgISq">electronic</a> imaging devices of both <a href="/facts/Analogue_electronics/Bnlnfwwv">analog</a> and <a href="/facts/Digital_electronics/3kJcKbkw">digital</a> types, which include <a href="/facts/Digital_camera/LSGTserm">digital cameras</a>, <a href="/facts/Camera_module/VIaqyVN5">camera modules</a>, <a href="/facts/Camera_phones/EzCfpkdl">camera phones</a>, <a href="/facts/Optical_mouse/qeXRlrop">optical mouse</a> devices, <a href="/facts/Medical_imaging/pL6JyJEp">medical imaging</a> equipment, <a href="/facts/Night_vision/tm6ToQgg">night vision</a> equipment such as <a href="/facts/Thermography/DWxF0CsD">thermal imaging</a> devices, <a href="/facts/Radar/jk9BTbFA">radar</a>, <a href="/facts/Sonar/245ooRW7">sonar</a>, and others. As <a href="/facts/Technological_change/7djdPWQ4">technology changes</a>, electronic and <a href="/facts/Digital_imaging/nTNga50f">digital imaging</a> tends to replace chemical and analog imaging. </p><p>The two main types of electronic image sensors are the <a href="/facts/Charge-coupled_device/l6xffIcz">charge-coupled device</a> (CCD) and the <a href="/facts/Active-pixel_sensor/6Trt4SWj">active-pixel sensor</a> (<a href="/facts/CMOS/7g2EwHGA">CMOS</a> sensor). Both CCD and CMOS sensors are based on <a href="/facts/Metal%25E2%2580%2593oxide%25E2%2580%2593semiconductor/eTDJT2Km">metal–oxide–semiconductor</a> (MOS) technology, with CCDs based on <a href="/facts/MOS_capacitor/eTDJT2Km">MOS capacitors</a> and CMOS sensors based on <a href="/facts/MOSFET/eTDJT2Km">MOSFET</a> (MOS field-effect transistor) <a href="/facts/Amplifiers/pnRgxncC">amplifiers</a>. Analog sensors for invisible radiation tend to involve <a href="/facts/Vacuum_tube/VHd1BNLq">vacuum tubes</a> of various kinds, while digital sensors include <a href="/facts/Flat-panel_detector/CtxzbvGM">flat-panel detectors</a>. </p>